Paste rosin size containing viscosity depressant

ABSTRACT

PASTE ROSIN SIZE A 150*-200*F. CONTAINING 0.5%-5% OF A WATER-SOLUBLE ALKANEPOLYOL WHICH HAS A MOLECULAR WEIGHT BELOW 250 AND A BOILING POINT ABOVE 150*C. POSSESSES LOW VISCOSITY AND DECREASED TENDENCY TO DEVELOP A HARD, BRITTLE, FOAMY CRUST WHEN EXPOSED TO THE AIR IN THAT TEMPERATURE RANGE.

United States Patent 3,577,402 PASTE ROSIN SIZE CONTAINING VISCOSITY DEPRESSANT Robert Alan Dorbransky, Stamford, Conn., assignor to American Cyanamid Company, Stamford, Conn. No Drawing. Filed July 24, 1968, Ser. No. 747,132

Int. Cl. C08l1 11/00 US. Cl. 260-97 2 Claims ABSTRACT OF THE DISCLOSURE The invention relates to paste rosin size of decreased viscosity and of decreased tendency to form a hard, brittle, foamy crust when exposed to the air at normal elevated temperature.

Paste rosin size at normal temperature is a viscous aqueous solution containing 60%80% by weight of papermakers rosin which has been saponified to the extent of 75% or more, and is in wide use as a sizing agent in the manufacture of paper; cf. Di Placido US. Pat. No. 3,390,004.

In general, the higher its content of rosin size the higher is its viscosity. To minimize the cost of shipping water, paste rosin size is generally shipped at the minimum water content at which it is pumpable.

The viscosity of paste rosin size decreases (and its pumpability improves) with rising temperatures, and hence most paste rosin size today is shipped and stored at maximum practical temperature, in the range of 150 F.200 F. and generally close to 200 F.

A serious problem exists with such size, in that the surface of the size changes when exposed to air at normal shipping or storage temperature. The surface paste rosin size loses water rapidly by evaporation and changes to a hard, brittle foamy crust. This crust does not readily re-dissolve in the size and is troublesome to remove. If not removed but is crushed, the resulting particles tend to clog pumps and screens and to appear as specks in the finished paper. Such specks are highly undesirable.

The discovery has now been made that paste rosin size which has a small dissolved content of certain polyols has a substantially lower viscosity than comparable size which contains no polyol and that such size does not form a hard, brittle, foamy crust when exposed to air for long periods of time in its normal shipping and storage temperature range. In preferred embodiments the viscosity of the size is decreased more than 50% by the presence of less than of the polyol, and the size does not form such crust when exposed to the air for as long as 24 hours at temperatures as high as 200 F.

The paste rosin sizes referred to above may be paste gum rosin size, paste wood rosin size, and paste tall oil rosin size; and the paste rosin sizes made by saponification of rosins which have been reacted with minor amounts of 3,577,402 Patented May 4, 1971 lCC fortifying or anti-crystallizing agents, for example, maleic anhydride, fumaric acid, acetylenedicarboxylic acid, dehydrated citric acid, saliginin, formaldehyde, etc.

The polyols which are present in the size of the present invention are the water-soluble alkanepolyols which have a boiling point above C. and a molecular weightless than 250. Best results so far have been achieved with water-soluble alkanediols having molecular weights less than 125.

Amongst the alkenepolyols suitable for use in the present invention are mannitol, sorbitol, .pentaerythritol, glycerol, neopentyl glycol, 2,3-hexylene glycol, 1,3-butylene glycol, 1,2-propylene glycol and ethylene glycol. The boiling points of the agents are substantially above 150 C., s0 that they are substantially non-volatile even at the normal shipping temperature of paste rosin size, and their molecular weights are below 25 0.

A significant decrease in the viscosity of paste rosin size is caused by the presence of /2%, based on the weight of rosin size solids, of the alkanepolyol in the size, and this amount is accordingly deemed the minimum practical amount of polyol that is economically present.

On the other hand, the decrease in viscosity afforded by the presence of more than 5% of the polyol (calculated on the same basis) is slight. Roughly 73 of the decrease in viscosity which is effected by a massive amount (20%) of the polyol is effected by only 5% of the polyol, so that this latter amount (which is more than that required to solve the problem of crust formation in preferred instances) is deemed the practical maximum for the amount of polyol which need be present. The most effective part of the range, per unit weight of polyol present and practicality of results, is the range between 2% and 4% which is therefore preferred.

The sizes of the present invention can be manufactured by introducing the desired polyol (or mixture of polyols) into the aqueous alkali metal alkali solution which is used to saponify the rosin, or by introducing the polyol into the finished size. In the continuous automatic manufacture of paste rosin size such as is shown in the Di Placido patent, the polyol can be continuously metered into the stream of alkali metal alkali as it enters the emulsifier. It is thus uniformly and automatically incorporated into the size.

The resulting sizes are stable on storage for extended periods of time at 180 C. in closed containers. The presence of polyol within the specified range, does not decrease or increase significantly the capacity of the size to impart water-resistance to paper.

The invention will be further illustrated by the examples which follow. These examples illustrate preferred embodiments of the invention and are not to be construed as limitations thereon.

EXAMPLE 1 A sample of commercial paste rosin size having a viscosity of 2900 centipoises at 71 C., a solids content of 76% by weight, a free rosin acid content of 11% (equivalent to 89% saponification) and 1% sodium chloride based on the weight of solids therein, is heated to F. The size is prepared by saponification of a mixture of fumarated rosin and formaldehyde reacted rosin with sodium hydroxide, by the procedure of Example 3 of 4 DErrico et a1. application Ser. No. 536,538, now US. complished by 10% of the glycol and about of the Patent No. 3,400,117. reduction in viscosity which is accomplished by 20% of A sample is withdrawn and into it is stirred 2.66% the glycol. based on the weight thereof, of a 76% by weight aqueous EXAMPLE 3 solution of one of the polyols shown in the table below, after which the viscosity of the resulting size (containing The following illustrates the response of several paste 3.5% by weight of polyol based on the weight of rosin rosin sizes to the viscosity depressing effect of polyols. solids therein) is determined at 71 C. The solids content of the sizes is in the range 70%78%. The sample is tested for its tendency to form a hard, They contain 10%15% free rosin acids (i.e., the rosin brittle, foamy crust by half-filling a test tube with the content thereof is 90%85% saponified) and the viscossize, and placing the test tube (without a stopper) for 24 1O ities are determined at 71 C.

Paste rosin size Viscosity of size Viscosity Percent Name eentipoises Name Percent 1 Ccntipoises 1 decrease Number 1 Heat treated gum rosin 2,500 Propylene glycoL- 1. 65 1, 600 36.0 2 Disprogortionatcd tall oil 12, 340 ..do 3. 6, 340 48, 5

rosin 3 Furnarated \vood rosin 1.000 do 3. 5 500 50.0

1 Based on total solids in size. 2 After addition of the polyol.

3 Prepared by saponifying gum rosin with NaOH to 77% solids and free acid.

4 Prepared by heating tall oil rosin to 225 O.300 O with a disproportionation catalyst for minutes and then saponiiying to 78% solids and 10% free acid content.

6 Prepared by heating 1 mol of wood resin with mol of iuinaric acid at 200 C. and then saponifying to 70% solids and 11% free acid content.

hours in a constant temperature bath at 100 C. Failure EXAMPLE 4 of such crust to form in 6 hours indicates that the size The Size prepared by the procedure of run 8 of is sat1sfactory in this respect. The procedure 18. repeated ample 1 is kept for 3 months in a closed container at With 1116 other P Y shown In the table, and Wlth an 1111 180 F. Its viscosity, its resistance to foamy crust formatreated sample as control. Results are as follows: 30 tion when exposed to the air at 100 C. and its properties Polyol present Viscosity of size 2 Agount M01 Genti- Percent of foamy Name weight Percent 1 poises decrease crust 3 Run No.2

1 None (control) 2,900 Severc 2 Mannitol 182 3.5 2, 740 4.1 None. 130 3. 5 2, 000 10. 6 Do. 92 3. a 2, 300 20. 6 Do. 104 3. 5 1, s00 37. 9 Do. Ethylene glycoL 62 3. 5 1, 650 43. 0 Do. 1,3-butylene glycoL- 90 3. 5 1, 575 45. 6 Do. 8-. 1,2 propy1enc glycol. .76 3. 5 1, 540 46. 9 Do. 9 2,3-hexylene glyeol 118 3. 5 1,440 50. 5 Do.

1 Percent present, based on weight of total solids in size. 2 At 71 (3., after addition of polyol. 3 After 24 hours in open half-filled test tube at 100 C. 1 Crust resembles a dry honeycomb about 14 thick.

EXAMPLE 2 as sizing agent for paper do not change noticeably during the interval. The following illustrates the effect of var1at1ons 1n the 1 l i a t of a Preferred P Y I as Viscosity PP 1. Paste rosin size having an effective dissolved content The Procedure of 11111 8 of Example 1 1S repeated 3 in the range of 0.5 %-5 based on the weight of resin number of times, the amount of th propylene g y size solids therein, of 2,3-propylene glycol as agent debeing varied as is shown in the table below. creasing the viscosity of the size and the tendency of the size to form a hard, brittle foamy crust when exposed to air at 150 F.200 F.

2. Paste rosin size according to claim 1 wherein the weight of 2,3-propylene glycol is 2%-4% of the weight Viscosity of size 2 0f I'OSiH size solids in said size.

4 P I; Pereent centi peii s e s 13633 1 228 6 References Cited 2, 900 UNITED STATES PATENTS 31233 531% 2,573,024 10/1951 Howell 106 238 f ggg g'-g 2,881,084 4/1959 Watkins 106-238 11540 :8 3,390,004 6/1968 Di Placido 106-238 1 228 gg 3,433,659 3/1969 DErrico et a1 106-238 ggg 94g FOREIGN PATENTS 601 467 7/ 1960 Canada 260-97 0H OHCHOHCH r nt b d on 4 th eggtll veight of solid; $5.1m? 1,045,400 10/1966 Great Britain 260-97 DONALD E. CZAJ A, Primary Examiner W. E. PARKER, Assistant Examiner The data show that 5% of the propylene glycol accomplishes about A of the reduction in viscosity which is ac- 106237; 162168,

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 577, O2 Dated Max 4, 1971 Inv nt fl Robert Alan Dobranskv It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, first table, last column heading, "Agount should read Amount Column 5, second table, line 68, second column of table "654" should read 6 +5 Signed and sealed this 3rd day of August 1971.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. WILLIAM E. SCHUYLER, JR. Attesting Officer Commissioner of Patents FORM 7 0-1050 (10-69) USCOMM-DC 60376-P69 9 \LS GOVERNMENT PRINUNIS OFFICE I969 0-355-33 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 577, LL02 Dated May 4, 1971 lnve t fl Robert Alan Dobranskv It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, first table, last column heading, "Agount" should read Amount Column 3, second table, line 68, second column of table "65 should read 6R5 Signed and sealed this 3rd day of August 1971.

(SEAL) Attest:

EDWARD M.FIETCHER,JR. WILLIAM E. SCHUYLER, JR. Attesting, Officer Commissioner of Patents FORM po'1o5om'sg) uscoMM-oc suave-ps9 U 5 GOVERNMENT PRINTING OFFPCE 9S9 0-366-33 

